Bag closing machine



1951 F. F. LINDSTAEDT ET AL 2,571,460

BAG CLOSING MACHINE Filed Feb. 2, 1946 2 Sheets-Sheet l [N V EN TORSFran k E L/nasfae d7 C/mr/ e s Fis Cher ATTORNEY 1951 F. F. LINDSTAEDTET AL 2,571,460

BAG CLOSING MACHINE Filed Feb. 2, 1946 2 Sheets-Sheet 2 V INVENTORSFrank E Lindsf'aed-f' BY Char/e s Fischer ATTORNE. Y

Patented Oct. 16, 1951 2,571,460 BAG cIIosING MACHINE Frank F.Lindstaedt, San Anselmo, and Charles Fischer, Corte Madero, Calif.

Application February 2, 1946, Serial No. 645,044

3 Claims.

The present invention relates to improvements in bag closing machines,and has particular reference to a machine for folding and sealing waxedpaper bags, although the principles involved may be applied to otherbags, particularly cellophane bags made of synthetic material.

The bags under consideration are of the fiat type, such as are commonlyused for potato chips and similar articles of food.

Bags of this type have no flat bottom and cannot be easily carriedthrough a machine for the various closing operations in uprightposition.

It is proposed, therefore, in the present invention, to feed the bags tothe machine in an inclined position and to guide the bags through themachine gradually changing to horizontal position, with a neck portionof each bag confined between two endless belts, the filled body portionsadvancing on one side of the belts and the ends on the other side of thebelts.

It is further proposed to perform all the operations incident to theclosing of the bag on the projecting end on one side of the belts incontinuous succession, whereby the machine is rendered completelyautomatic and is made to handle bags at great speed, with a presentcapacity of approximately two hundred and forty bags per minute.

It is still further proposed to provide a special feed means for themachine whereby the bags may be fed by the mere dropping in promiscuousorder, and which is also adapted for'feeding bags of different sizes.

Bags of the type under consideration are usually manufactured withserrated edges at the open end, one edge projecting somewhat beyond theother to facilitate opening of the bags for filling operations.

For the purposes of our machine and for effecting a perfect seal, it isdesirable that the edges be cut to uniform, straight lines, and it isproposed in the present invention to provide a novel cutting means tocut the edges to size before the beginning of the folding operation.

It is further intended to provide for a double fold of the end edges ofthe bags, the two folds being made in two successive operations.

Waxed paper bags have been sealed heretofore, by utilizing the wax as asealing medium, under the influence of heat. But better results areobtained by applying a special sealing medium,

such as plastic wax, and it is proposed to pro vide means, in thecontinuous operation of the machine, for temporarily unfolding the foldspreviously made and for applying a special sealing medium to one of the.contacting faces, in the presence of heat.

And finally, it is,proposed to effect a rapid cooling of the sealedbags, and still in the presence of sufficient heat to keep the wax frombecoming sticky and from interfering with the perfect operation of themachine.

Further objects and advantages of our invention will appear as thespecification proceeds, and the novel and interesting features of ourbag closing machine will be fully defined in the claims attached hereto.

The preferred form of our invention is illustrated in the accompanyingdrawings, forming part of this application, in which:

Figures 1A and 1B show a plan view of our bag closing machine, Figure 1Bbeing a continuation of Figure 1A, and an inclined conveying means beingshown as viewed perpendicularly;

Figure 2, a transverse section taken along line 2-2 of Figure 1A;

Figure 3, a rear view of a portion of our machine, certain parts beingshown in section;

Figure 4, a section taken along line 4-4 of Figure 3;

Figure 5, an enlarged rear view of part of the folding and sealingmeans, with a cover plate removed;

Figure 6, a plan view of the parts shown in Figure 5; and

Figure 7, a fragmentary cross-section taken along line '!1 of Figure 3.

While we have shown only the preferred form of our invention, we wish tohave it understood that various changes or modifications may be.

made within the scope of the claims hereto attached, without departingfrom the spirit of the invention.

Referring to the drawing in detail, our machine comprises, in itsprincipal features:

A pair of endless belts l arranged in superimposed relation so as topresent confronting stretches 2 between which the neck of each bag isgripped and advanced, with the main body portion of the bag on one sideof the belts and a short end of the bag projecting on the other side ofthe belts;

Means generally indicated at 3 for feeding the bags to the belts;

Means shown at 5 for trimming the projecting ends of the bags;

Means shown at 6 for folding the end of each b Means shown at i foradding a second fold to the end of the bag;

Means shown at 8 for unfolding the two folds, for applying a strip ofglue to the bag material at the fold in the presence of heat, and forrefolding the folds upon the glue, and

Means indicated at 9 for cooling the folds in the presence of moderateheat.

The two belts I are narrow so as to engage only a small portion of theneck of each bag, and are mounted on suitable grooved pulleys l0. Theyare preferably V-shaped in cross-section, and their confrontingstretches run in guide grooves IIJ'.

Suitable means (not shown) are provided for tensionin'g the belts sothat the flat confronting faces grip the bags with suflicient frictionfor advancing the same. They both operate, by means to be describedlater, at the same surface speed. Means are provided, as at H to apply agraphite lubricant to the belts.

The bags, indicated at A, are fed to the belts in inclined position bythe means illustrated at 3, which is intended for feeding filled bags oftwo or more different sizes.

For feeding the smaller size of bag, we use an inclined feedway ofconsiderable length, comprising a channel-like lower section H (seeFigure 2) adapted to receive the filled portion of the bag, and a flatupper section |2 slightly setoif with respect to the lower section andadapted to have the upper portion of the bag ride there- The bottom ofthe channel is formed by a belt |3 running over a pair of cylindricalpulleys l4 and supporting the lower side of the filled portion of thebag for advancing the latter when the belt is moved.

With small bags, the weight of the bag is not always sufiicient toinsure positive advance of the bag at belt speed, and we, therefore,provide a second belt l5 on the lower channel wall to bear against andadvance the bottom end of the bag. This belt I5 is trained over pulleysl5.

For advancing larger bags, we provide a second channel or trough |6adjacent the lower end of the first channel, this trough having a thirdbelt adapted to have the filled portion of the larger bags rest thereonand a ledge |8 against which the bottom end of the bag rides. The

larger bag, thus resting on the belt bridges the channel II for theshorter bag and has its upper end ride on the flat upper section l2.

We have found from actual experience that the larger bag is sufiicientlyheavy for advancing by a single belt. The belt I1 is trained over thepulleys |4, its upper stretch being raised to the desired elevation byrollers l1 and being bent into the desired plane by deflectors IT".

The two belts l5 and H are mounted on an adjustable frame structure 19whereby the exact distance of these belts from the upper section |2 maybe adjusted to insure proper overlap of the open end of the bag oversection l2 for feeding between the belts. For the purposes ofadjustment, we provide brackets 20 secured to the frame structure l9 andslidable on the table 2|, the brackets being secured to the table bymeans of set screws 22 passing through slots 23.

As the bags approach the belts l, the overlapping ends are flattened bymeans of a rod 26 and are fed underneath two short endless belts 21trained over a conical pulley 21 and the pulley H). The latter beltscooperate with a flat section 28 of the main table 2| in compressing thetwo thicknesses of the upper end of the bag and in feeding said upperend between the two main belts It should be noted that all the beltsthus far discussed, namely the belts I, l3, l5, l1 and 21 4 run at thesame surface speed so that each bag runs smoothly through the entiremachine.

The feedway is supported on suitable legs 3!) reinforced bycross-members 3|.

After the neck of the bag has been gripped between the belts for furtheradvance, its projecting end approaches the trimming means 5. The end issupported on a horizontal plate 35 (see Figure 4), and is urged upon theplate by a fiat spring 36, the forward end of which is slotted, as at31, to admit the rotary saw 38, the lower portion of which extends for ashort distance into a kerf 39, so as to trim off the extreme end of thebag.

The saw 38 is in the form of a small disc and has hack saw teeth in thecircumference thereof. The blade is very thin, and the kerf 39 is justwide enough to accommodate the teeth of the saw. We find that, due tothis arrangement, the saw will perform its function practicallyindefinitely, without requiring any attention. It is driven by anindependent motor 4| through a belt 4|, as shown in Figure 4, and thetrimmings are guided into a box 49.

After the end of the bag has thus been trimmed and squared, it entersthe folding means indicated at 6 and The folding means comprises in itsprincipal features, a mandrel 45, and two plow shares or mold boards 46and 4'! cooperating therewith. The mandrel is in the form of a thinmetal strip secured upon a section 48 of the main frame structureadjacent the belts and in the horizontal plane of the contact face ofthe lower belt, so as to form a continuation of the plate 35.

The mandrel comprises two sections 49 and 50, the former being somewhatwider than the latter. The two plow shares 46 and 41 are secured upon aremovable plate 5| adapted for fastening upon an upper frame section 52by means of two screws 53, the plate being guided into its properposition by means of two pins 54 adapted to be received in correspondingholes in the plate. The latter has two handles 55 by means of which itmay be conveniently manipulated for attachment and removal.

The first plow share 46 cooperates with the first mandrel 49 in throwingthe first fold. The plow share is shown in cross-section in Figure 7 andcomprises a plate 56 overlying the mandrel and curved around the edge ofthe mandrel and underneath the same so as to bend or fold a narrow stripof the projecting bag end underneath the mandrel.

At the forward end of the first mandrel section is provided an escapeslot 51 through which the lower fold is allowed to pass upon the upperface of the second mandrel section 55, the fold being guided by a lip'58 at the rear end of the second mandrel. A leaf spring 58 cooperateswith the lip in creasing the first fold.

As the folded end passes over the second mandrel section 50, which isnarrower than the first section by the width of the first fold, it isagain folded by the second plow share 41 in the manner previouslydescribed in connection with the first plow share.

Upon leaving the second mandrel section, the two folds, which are nowunderneath the mandrel, pass over "an anvil 60 which cooperates with asecond leaf spring 6| in creasing the second fold.

It should be noted in this connection that the trimming means shown at 5bears a definite relation to the other elements of the machine andparticularly" to the-folding means. One of'its objects is, as previouslystated, to eliminate-thesaura-ted edge of the bag commonly used in theseoperations: But it would be-just asnecessary if a previously squaredbag-were used, for thefollowing reasons.

Where thebags are used for accommodating potato chips, it is a fact,that although the same weight of chips be used, theexpansionof the bagsvaries with the shape of the chips, which again causes variations intheoverall length of the bags; For-varying shapes of chips the overalllength of the bag may vary as much as A of an inch, and it is essential,of course, that when the bags reach the folding means, the. projectingends be cut to a common standard. If they are too long, they would notenterthe mold board, and if they are too short, they would not form asatisfactory fold.

Furthermore, it frequently happens that during the feeding and conveyingoperations the two sheets of the bag shift with respect to one anotherwith the result that one' sheet would project beyond the otherwhen' thebag reaches the folding means, again with unsatisfactory results.

And. finally, the projecting end edges should not only be cut to auniform standard, but the standard must bear a definite relation to thefolding means, As has been pointed out, the second mandrel section isnarrower than the first section by the width of the. first fold and itis necessary, therefore, in order to. prevent binding at the entranceinto the second. folding means, that the projecting end be first sizedto make the first fold correspond in width to the difference in widthbetween the first and second mandrel sections.

The mandrel thereupon continues in the same plane to terminate into athird section 62 which is still narrower than the second section, and isin the form of a thin strip substantially the width of the folds. Atthis time the two folds are underneath the mandrel and the body portionof the end of the bag rides on top of the mandrel.

The third mandrel section guides the end of the bag over the gluecontainer 63, which is filled to a desirable height, with a suitableadhesive, such as plastic wax. This container has a narrow glue-applyingwheel 64 revolvable therein, and this wheel is rotated, by means laterdescribed, at the same surface speed as that of the bag advancing beltsl. The wheel is positioned in 'alinement with the third section of themandrel as thus far described, and is intended to apply a strip of glueto the undersurface of the body portion of the bag end.

For this purpose, it is necessary to separate the two folds from thebody portion while the ba passes the glueing wheel. This is accomplishedby bending or twisting the mandrel, the first portion of which ishorizontal, into vertical position and away from the belts I so as topass around the wheel, as shown in Figure 6 and by re-bending it intohorizontal position after it has passed the wheel. This third mandrelsection thus bends the two folds previously formed away from the bodyportion of the bag end and guides the two folds around the wheel insubstantially vertical position while the wheel applies a strip of glueto the underface of the body portion of the bag end. A leaf spring 65presses the body portion of the bag end upon the glue wheel, and ispreferably split to bear on the bag end on opposite sides of the wheel.

After the bag end has passed the glueing wheel.

the mandrel section bends back into horizontal position for a shortdistance and a third plow share 66 cooperates with the mandrel sectionin again folding the two folds upon the body sec!v tion of the bag end,the third plow share risinginto the plane of the mandrel at the forwardendof'the'latter, as at 6.1, where the leaf spring 68 cooperates with itin pressing the body portion with its strip of' adhesive upon the folds.

During the foldingprocess the bags are sub-1 jected to moderate heat bythe electric heater 69 disposed underneath themandrel. The gluecontainer is subjected to more intense heat: by the twoheaters 10-di'sposed' on opposite ends of the container.

Theheat at the mandrel and the plow shares isapplied to prevent the bagsfrom sticking: or adhering to the metal surfaces. In case any troubleshould develop at the-plow shares duringthe operation of the machine,the plate 51 may be easily removed to render all the parts accessibleforcleaning.

After the glue has been applied, the bag ad vancesto the cooling stationindicated at 9. This. station comprises a plurality of spaced anvils Hhaving guide lips 12 and fiat sections 13 disposed in the plane of themandrel and having leaf springs 14 cooperating therewith in pressing thefolded bag ends upon the anvils.

This process is carried out in the presence of moderate heat, anelectric heater l5 being arranged underneath the anvils and spacedthere!- from. This heat prevents the bags from stick.- ing, while theleaf springs 14 serve to conduct the heat away fromthe bag ends.

Substantially at the glue container, the table 2| gradually curves awayfrom the inclined position shown in Figure 2 into a horizontal plane,and a series of belts 18 are provided for the final advance of the bagsand for discharge of the sealed bags upon a transverse conveyor 11.

Any suitable drive mechanism may be arranged for driving the differentelements at the desired speed. In the arrangement shown, the reductiongearing in housing is actuated by a motor (not shown) through a pulley8|.

The reduction gearing drives, through belt 82, the glueing wheel 64 inthe glue container 63. It also drives, through chain 83, a shaft (notshown) underneath the shaft 84, which drives the shaft 84 throughgearing 85, and also chains 86 and 81.

Shaft 84 drives the pulleys ID on which the main belts I are mounted.Chain 86 operates shaft 88 on which the pulleys 89 for the conveyorbelts 16 are mounted.

Chain 8! drives shaft 90, which, through suitable gearing (not shown)drives the pulley IQ for the belts l3 and H. Shaft 90 further drives,through chain 9|, a shaft 92 which is connected, through gearing notshown, for driving pulley l5 and belt 15.

In operation, the bags, which have been previously filled and weighed,are deposited by the operator upon the feedways in any order desired,taking care that the smaller bags ride on the belts l3 and I5, while thelarger ones ride on the belt l'l.

They may be fed promiscuously, and the machine, as at present operated,keeps two operators busy at the feeding end. As the bags advance, withtheir upper ends on the plate l2, the rod 26 flattens the upper ends andthen the belts 2'! feed the ends between the belts l.

The bags then advance in continuous procession to be trimmed and squaredat the station 5, folded and double folded at G and'l, glued at 8 andfinally cooled at 9.

- The glueing operation includes the partial unfolding, applying of theglue, and the re-folding as herein described. The heat applied at thedifferent stations prevents the bags from sticking to the metallic partsof the machine.

' We claim:

1. In a bag closing machine, a pair of belts having confrontingstretches for advancing a bag therebetween with an end portion of thebag projecting beyond the belts, a platform adjacent the belts adaptedto have the projecting end ride thereon and having a longitudinal kerftherein, a leaf spring overlying the platform and adapted to urge thebag end upon the platform and having a slot registering with the kerf,and a rotary saw mounted over the platform and engaging in the, slot andin the kerf for trimming the bag end as the latter advances.

'2. In a bag closing machine, a pair of belts having confrontingstretches for advancing a bag therebetween with an end portion of thebag projecting beyond the belts, a platform adjacent the belts adaptedto have the projecting end ride thereon and having a longitudinal kerftherein, a leaf spring overlying the platform and adaptedto' urge thebag end upon the platform and having a slot registering with the kerf,and a rotary saw mounted over the platform and engaging in' the slot andin the kerf for trimming the bag end as the latter advances, the sawhaving hack saw teeth in the circumference thereof and the kerf beingjust wide enough to accommodate the said teeth.

3. In a machine of the character described, means for cooling the sealedend of a bag, comprising a series of alined anvils arranged inlongitudinally spaced relation and having flat section and downwardlycurved guide lips, means for guiding the sealed end of the bag to passover the anvils, and a leaf spring cooperating with each anvil in urgingthe bag end upon the same and operable to serve as a means forconducting heat away from the sealed end.

FRANK F. LINDSTAEDT.

CHARLES FISCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED- STATES PATENTS Number Name Date 1,090,499 Poler Mar. 17, 19141,374,593 Lundin Apr. 12, 1921 1,919,175 Smith July 18, 1933 2,015,507Arnold et a1. Sept. 24, 1935 2,018,806 Richard Oct. 29, 1935 2,018,807Richard Oct. 29, 1935 2,070,822 Beardsley et a1 Feb. 16, 1937 2,245,063Allen June 10, 1941 2,253,036 Kimple et a1. Aug. 19, 1941 2,272,323Lawrence Feb. 10, 1942 2,309,760 First Feb. 2, 1943 FOREIGN PATENTSNumber Country Date 93,610 Switzerland May 17, 1920

